This invention relates to cargo rail systems for aircraft, and more particularly to a system which incorporates movable cargo rails and a cargo conveyor system to assist in automating the aircraft loading and unloading process.
When palletized cargo is transferred to a cargo ramp on a military cargo aircraft, it is often not properly centered on the ramp and it may not be in good alignment with the axis of the aircraft. In order for the pallets to move forward, they must be both aligned and centered on the ramp. This is because the left and right edges of the pallet must fit underneath the fixed cargo floor cargo rails which are standard on military aircraft. Centering and alignment is currently typically provided by a pair of cargo rails which are flared at the aft end of the ramp so that as the pallet is put onto the ramp it is "funnelled" into position. In some cases the orientation of the rectangular pallets is different on the truck or material handling equipment than it is on the aircraft. For instance, the pallet may ride in the truck with the long dimension fore and aft, but in the plane the short dimension is fore aft. At some point, the pallet must be rotated 90 degrees. This rotation typically occurs on the cargo ramp using omnidirectional rollers and manpower. However, the cargo ramp funnel rails mentioned above interfere with this invention.
Another problem which greatly slows down the cargo loading and unloading process is moving the pallets along the cargo bed floor of the aircraft. Current practice includes pushing the load by hand as well as using a winch-driven cable to pull the load along the aircraft. There are some problems with these methods, however. One problem is that personnel are required in the cargo bay which may be exposed to chemical, biological, or conventional weapons threats. Manual pushing of the loads is slow, dangerous, and inconsistent. Cable winching of loads can move only one pallet at a time. Furthermore, none of these methods provides a positive location of the load at all times. For instance, if the aircraft is pointed downhill, alternative means of stopping or slowing the load is required.
Therefore, what is needed is a device which can align and center a pallet for widthwise or lengthwise storage without interfering with the rotation of the pallet. What is further needed is an automated device for moving palletized cargo along the length of a cargo aircraft without hands-on connection or force. This device should also be capable of positively locating and locking in place palletized cargo at all times.